The disclosure relates to a system for preparing an opening created on an organic wall, comprising: —a supporting body defining a longitudinal axis and having a proximal portion and a distal portion adapted for insertion through the opening —external clamping elements deployable in an outwardly flaring arrangement relative to the supporting body and able to cover portions of an annular surface of said wall and—biasing elements arranged to tighten and juxtapose said external clamping elements on said body in order to progressively deform said annular surface so as to shape on said wall a tubular portion extending along the longitudinal axis and form an anchoring clamp consisting of said external clamping elements.
